Remigius (aka Remi or Rémy) was Archibishop of Reims c.459-533. He is best known for the conversion and baptism of the first Christian King of the Franks, Clovis I.

This is quite a difficult window to unravel as some of the scenes (particularly panels 3, 4, 19 and 20) do note relate to any of the stories of St Remigius in any of the known textual sources. Nor do they appear in other image cycles. Even the great Yves Delaporte admitted defeat here. One can only assume that the designers of the window had access to a now lost source of legends about the saint.
Other episodes, such as the miraculous appearance of the Holy Chrism used in the French coronation rituals, or the creation of wine at a feast (obvious and deliberate echoes of Christ's miracle at Cana) are widely depicted and also appear sculpted on the north transept portal of Reims Cathedral.

See Delaporte & Houvet pp. 266-71 for more on the background to this window and notes on its condition.